JPS6116420Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a nut flat washer used under a high-strength bolt or a bolt nut.

Bolt tightening used when it is necessary to introduce the required axial force into high-strength bolts or bolts (hereinafter referred to as bolts) used to fasten members of steel structures or other metal structures (hereinafter referred to as structures) One of the construction methods is the nut rotation method.
It is usually enforced using the following steps:

(1) After gathering the fastening pieces at the member fastening part of the target structure, use an appropriate number of temporary bolts to tightly attach the pieces (Figure 1).

(2) Insert the bolt into the remaining bolt hole and apply a bolt axial force equivalent to a fraction of the final tightening force (i.e. bolt axial force) (referred to as primary tightening). This primary tightening work is performed, for example, by using a torque wrench to rotate the nut to a required torque value.
The temporary tightening bolts will be replaced with bolts one after another and the primary tightening work will be performed.

(3) Mark the starting point through the bolt, nut, plain washer, and material to be tightened as shown in Figure 2A.

(4) Starting from the state where the primary tightening has been completed, the bolt tightening work is completed by final tightening, that is, by applying a predetermined amount of rotation of the nut to the bolt shaft. When the nut is rotated and tightened by final tightening, only the nut rotates and the mark illustrated in FIG. 2A becomes misaligned, resulting in the state shown in FIG. 2B. This amount of deviation indicates the amount of rotation of the nut relative to the bolt axis, and if the angle is at the required angle or within the allowable range, it is assumed that the corresponding required axial force has been introduced into the bolt. to decide.

When a bolt is tightened by the nut rotation method using such a procedure, the amount of rotation of the nut is confirmed by, for example, the positional relationship between the mark and the ridgeline of the nut, as shown in FIG. In the case of commonly used hexagonal nuts, the central angle of each edge with respect to the axis is 60°, so unless a special measuring jig (such as a protractor board) is used, the accuracy of the angle that can be visually recognized is not very high. I can't wait. Furthermore, if the bolt or washer rotates together with the nut, it is very difficult to confirm the effective rotation angle of the nut.

Conventionally used flat washers are not designed to help confirm the rotation angle of the nut.

The present invention focuses on the points mentioned above, and in order to easily and accurately check the nut rotation angle when bolts are tightened by the nut rotation method, angles are set on flat washers at required intervals. It is characterized by having an indication scale.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 is an example of an angle indicating scale provided on a flat washer. That is, a case is illustrated in which a scale 10 corresponding to the central angle of 15 degrees of the flat washer 9 for the nut rotation method is provided.

Fig. 4 shows a state in which the bolt has been tightened by the nut rotation method using the flat washer 9 according to the present invention, and the nut rotation angle can be confirmed by counting the angle scale attached to the washer. can. It is easy to confirm the occurrence of co-rotation phenomenon,
Also, in cases where co-rotation is involved, bolts, nuts,
It goes without saying that the effective rotation angle of the nut can be easily read from the mark 8 marking the starting point on the flat washer and the material to be tightened, and from the angle indication scale placed on the flat washer.

As explained above, when tightening bolts using the nut rotation method, conventionally used flat washers (e.g. JISB1256 flat washers, JISB1186 high-strength hexagonal bolts for friction bonding, hexagonal nuts, and a set of flat washers) Since the nut does not have a mark as in the present invention, confirmation of the nut rotation angle tends to be inaccurate. When using the washer according to the present invention, the nut rotation angle can be easily and accurately and efficiently determined using the angle scale, and the conventional procedure for bolt tightening work using the nut rotation method can be changed when axial force needs to be controlled. It has the advantage of being able to proceed smoothly.

[Brief explanation of the drawing]

Fig. 1 is a sketch diagram illustrating the state of gathering of pieces at the joint of members of a structure, Figs. 2 A and B are sketch diagrams illustrating an example of the work procedure for tightening bolts using the nut rotation method, and Fig. 3 is a sketch diagram illustrating the state of gathering of pieces at the joint of members of a structure. FIG. 4 is a sketch showing an example of application of the flat washer according to the present invention. FIG. 4 is a sketch showing the state of completion of tightening when a bolt is tightened by the nut rotation method using the flat washer according to the present invention. 1... Structure member, 2... Splice plate, 3... Temporary tightening bolt, 4... Plain washer, 5... Nut, 6...
Material to be tightened (member part), 7... Bolt, 8
...Starting point mark for measuring the nut rotation angle, 9...
Plain washer for nut rotation method, 10...Angle scale.

Claims (1)

[Scope of utility model registration request] A flat washer for a nut rotation method, characterized in that a dot, a line, or a combination of dots or lines is embossed or engraved, or an angle indicating scale is applied with paint or the like on the surface or side surface or from surface to side.